Depends what router - many newer ones are K26 only.
For something like 4MB flash Linksys WRT54GL there is a limited amount of choice, and initial reports were that K26 much slower. K26 was unusable on my wrt54gsV1.1 when last tried (loaded but randomly crash). Anything over the last couple of years is 'experimental' basically you chose a mod author and find an option that works for you. There's no formal release or bug tracking system at the moment, but an open GIT repository keeps different versions forking too much!